This invention relates to a method and an apparatus for venting an inflatable restraint assembly and more particularly, to a method and an apparatus which selectively vents an inflatable restraint or xe2x80x9cair bagxe2x80x9d assembly at a predetermined time after inflation, based upon several factors such as occupant seat belt usage, weight, position relative to the restraint assembly, and crash severity.
Inflatable restraint assemblies, commonly referred to as xe2x80x9cair bagsxe2x80x9d or xe2x80x9ccurtainsxe2x80x9d, are typically deployed within a vehicle and selectively and inflatably expand into the passenger compartment of the vehicle when the vehicle is struck by or collides with another vehicle or object, thereby reducing the likelihood of injury to occupants of the vehicle.
Air bag or curtain assemblies are typically and operatively coupled to a controller and/or one or more sensors which detect a vehicle collision and which activate the air bags in response to such a detection. Particularly, an air bag is typically contained within an inflator can which includes a pyrotechnic gas charge or generator which is communicatively coupled to a controller and which is selectively discharged by the controller, effective to inflate the air bag. The inflated air bag reduces the impact of an occupant of the vehicle against interior vehicle components, such as the steering wheel, dashboard and windshield.
In order to further lessen the severity of the impact and deceleration of the occupant, some air bag assemblies include pressure activated vents which selectively allow gas to be vented or released from the inflated air bag once a predetermined pressure is reached, thereby allowing the air bag to controllably deflate when impacted by the occupant. One drawback with these types of assemblies is that the pressure activated vents do not always vent or deflate the air bag at an optimal rate or time. Other air bag assemblies utilize xe2x80x9cdual stagexe2x80x9d inflators which are capable of discharging gas into the air bag at two separate rates or output levels. While these xe2x80x9cdual stagexe2x80x9d inflator type air bag assemblies may reduce occupant deceleration under certain circumstances, they do provide for optimal venting of the air bag.
There is therefore a need for a method and an apparatus for venting an inflatable restraint assembly which allows the inflatable restraint assembly to be vented at an optimal time and rate.
A first advantage of the invention is that it provides a method and an apparatus for venting an inflatable restraint assembly or air bag which overcomes at least some of the previously delineated drawbacks of the prior systems, devices, and/or methods.
A second advantage of the invention is that it provides a method and an apparatus for venting an inflatable restraint assembly which allows an air bag to be vented at an optimal rate.
A third advantage of the invention is that it provides a method and an apparatus which utilizes one or more sensors to reliably determine the optimal time to vent an air bag and to vent the air bag at that time.
According to one aspect of the present invention, an inflatable restraint assembly is provided and includes an inflator can including an aperture; an air bag which is selectively and operatively disposed within the inflator can; a pyrotechnic gas generator which is disposed within the inflator can and which is effective to selectively inflate the air bag with gas; a door which selectively covers the aperture; and an actuator which is coupled to the door and which selectively opens the door at a predetermined time after the air bag is inflated, effective to allow the gas to vent through the aperture.
According to a second aspect of the present invention, a method is provided for venting an air bag. The method includes the steps of providing an inflator can for selectively inflating the air bag; forming at least one aperture within the inflator can; selectively covering the at least one aperture with a door assembly; measuring certain vehicle attributes; and selectively uncovering the at least one aperture at a certain time after the air bag has been inflated based upon the measured certain vehicle attributes.
Further objects features, and advantages of the invention will become apparent from the following detailed description of the preferred embodiment of the invention and by reference to the following drawings.